WIMBLEDON, England -- Venus Williams already had squandered four set points, but there still was one left, and it would level the match with Karolina Sprem. Williams tentatively approached the net. As her tight forehand landed in the green cord (and her backside skidded into the grass), she loosed a plaintive wail. It was, in retrospect, her last gasp.

Even a stunning and stupid mistake by chair umpire Ted Watts that cost Williams a point in the final tiebreaker probably wouldn't have made a difference because the truth has emerged:

The invincibility is gone.

Williams is still 6-foot-1 and her ground-stroking grunts are as prodigious as ever. But time and injuries have eroded her confidence and power. On Thursday, the two-time Wimbledon champion was just another second-round casualty.

Sprem, a 19-year-old Croatian, was not afraid. The 30th-ranked player on the WTA Tour slammed Williams around Centre Court and beat her decisively, 7-6 (5), 7-6 (6).

"I was playing everything what was I can," Sprem said in meandering English. But her meaning was clear.

"I said, 'Go in the net. Hit the first serve. Hit the ball.' Everything what I have, I was trying to hit."

There were times when Williams looked positively bewildered.

When she arrived in the interview room, her outlook hadn't changed. She spoke in a soft voice and seemed very emotional.

Do the players in the locker room detect a new vulnerability?

"I guess I'm not really thinking about what the next person thinks," Williams said. "I only really care about what I think.

"She just came out and felt like she had nothing to lose. She plays me like that."

The question was phrased another way. Does she feel as dominant now as when she won four Grand Slams out of six and was No. 1 in the world?

"I feel like when I step on the court, that the person playing me has to really believe that they can win against me," Williams said. "It's going to be very tough."

Since reaching the final here a year ago -- where she lost to sister Serena -- Williams has failed to reach even a Grand Slam semifinal. She missed the last five months of the 2003 season with an abdominal injury, passing on the U.S. Open. She lost in the third round of the Australian Open, her first tournament back, to fellow American Lisa Raymond. At the French, she fell to eventual champion Anastasia Myskina in the quarterfinals. And now, a second-round exit -- her worst result here since 1997, her first Wimbledon.

If Serena doesn't win this tournament, it will mark the first time since 1999 that one of the Williams sisters didn't hold a Grand Slam title. That would be a remarkable shift in the balance of power.

Given Venus' recent history, the loss against Sprem was not a massive surprise.

The two played last month in Berlin, on clay, and Sprem lost the semifinal match 7-6 (5), 5-7, 6-2. Of the total five sets between them, three ended in tiebreakers. Berlin was one of three tournaments in which Sprem has reached the semifinals, but this was the biggest win of her young career.

Williams, despite a raft of unforced errors, led Sprem 6-5 in the first set. Williams had two set points but couldn't capitalize. The second set was a struggle the whole way; Sprem led 4-1, but Williams broke her serve twice and forced a second tiebreaker.

Even with the scoring snafu, Williams found herself with a 6-3 lead -- three set points to level the match. In a situation like that, you would expect experience to reign. It didn't. Williams lost the last five points. When her final forehand sailed long, she ran to the net as fast as any of her approaches.

Now it was Sprem's turn to look stunned.

"I think I need more matches like today," Sprem said. "I need to play against bigger player. I need my confidence to go up. I'm young, and it's new for me. I just need to play more matches, that's all."

For Williams, there will be many questions as the summer spins toward the U.S. Open. Is her abdominal injury really healed? Are her more recent ankle and wrist injuries serious? Are her outside interests diluting her tennis? Does she still want to win as badly as she used to?

"What do you think?" she said to one particularly succinct question about her hunger.

"I don't know," Williams said. "I think you should just write what you think. I fought very hard. Even if I'm well or not well or injured or have had setbacks, I still did very, very well."

What about her recent dry spell in Grand Slams, a year without seeing a semifinal?

"Yeah," she said, oddly thoughtful. "It's been a little while."

And then there was something that sounded like a rationalization.

"I enjoy playing," she said. "I enjoy my life. I enjoy all the blessings that I receive. I think there's so many people who would love to be in my position. So I'll take advantage of it and keep enjoying it."